/library/oar/handle/123456789/97522 2025-11-06T15:11:34Z /library/oar/handle/123456789/129307 Title: An efficient HVAC design for research laboratories Abstract: Laboratories are very energy-intensive buildings and hence have a high carbon footprint. The aim of this dissertation was to improve the heating, ventilation and air conditioning (HVAC) design of such laboratories so as to make the system more efficient. This dissertation reviewed HVAC equipment available on the local market was reviewed to determine whether the equipment found was suitable for laboratories whilst still being compliant with applicable standards. The literature review was then followed by simulations conducted on Design Builder™ simulation software. The aim of the simulations was to reduce and/or reuse HVAC energy supplied to the indicated zones, in turn reducing the electrical energy required by the overall system. A superseded pre-existing 3D model was altered to match the final design of the University of Malta SLC Conservation and Heritage Labs. This included both a structural update and an HVAC systems update. The model HVAC system was divided into two setups. The first setup accounted for the HVAC systems utilised within non-laboratory zones, whilst the second HVAC setup was designed for laboratory zones. This was done because the ventilation from these two setups cannot be allowed to mix. The simulations accounted for population within the zones (including expected physical activity of the occupants, amount of clothing worn by occupants and the switching schedule) and the required HVAC performance to maintain the desired thermals, humidity level and ventilation flow rate. Initially the simulations, were used to determine the most suitable technologies for the considered case study. Once the variables were individually analysed a final simulation was run to identify the best energy reduction that can be obtained for the University of Malta SLC Conservation and Heritage Labs for the HVAC systems under consideration. The final simulation yielded an 8.9% improvement for the cooling demand and a 28.7% improvement for the heating demand. This equates to an overall reduction in the annual demand of 14.8%. In conclusion, the study provides a very much needed first look at lab energy consumption. Furthermore, the dissertation has a lot of potential for future studies to advance an already improved HVAC system Description: M.Sc.(Melit.) 2022-01-01T00:00:00Z /library/oar/handle/123456789/119666 Title: Development of an electronic probe for rock mass characterisation Abstract: While considerable technological advances have been made in different fields related to both soil and rock mechanics, there is a dearth of low-cost geophysical tools aimed at rock mass characterisation through pre-drilled small-diameter boreholes (as small as 60 mm). A literature review was conducted to understand the tools and methodologies currently in use for analysis. This was supplemented by site visits and hands-on experience to help familiarisation with borehole drilling operations, discontinuity logging in a soil and rock testing laboratory, rock mass discontinuity surveying and the use of downhole televiewers. While techniques and commercially-available tools exist and have previously been used locally, these do not provide an all-in-one solution, particularly because of their relatively large physical size and high cost. After establishing a set of design requirements, a small-diameter borehole 3D-scanning system was proposed. At its core, the system uses a miniature single point IR-ToF distance sensor that measures distance to the internal surface of the borehole as it rotates and moves along the bore axis. The data acquired is then processed to generate a 3D point cloud model of the borehole and its discontinuities (fissures). Processing includes the orientation of the point cloud data according to data provided by an orientation sensor. The distance sensor and orientation sensor were both selected and characterised through a series of experiments using hardware and software tools developed specifically for this purpose. The selected distance sensor was used to 3D-scan a physical model that emulated a segment of a fissured borehole. After validating the proposed system, a prototype instrument consisting of a downhole probe, a probe deployment system, and a ground station, was designed and built to test the technology in the intended operating environment. Each unit is made up of various mechanical and electrical parts such as electronic circuit boards, along with the necessary firmware. Field testing confirmed that the developed instrument was capable of obtaining the data needed to faithfully model a borehole and its discontinuities. Further testing is required to continue characterising the instrument in different operating conditions. Hardware and software modifications are also needed to address certain limitations that were identified during field testing. Description: M.Sc.(Melit.) 2022-01-01T00:00:00Z /library/oar/handle/123456789/107543 Title: EOG-based gaze angle estimation with varying head pose Abstract: This work addresses two major challenges in the field of electrooculography (EOG) signal processing, that of baseline drift and gaze estimation considering both stationary and non-stationary head conditions. Although several different baseline drift mitigation techniques have been proposed, the choice of technique and corresponding parameters is generally arbitrary. To this end, this work carries out a systematic performance analysis and applies these different techniques to the same recorded EOG data. This analysis has demonstrated that frequent resetting is the overall best-performing, followed by signal differencing, wavelet decomposition, high-pass filtering and polynomial fitting. To address the challenge of EOG-based gaze estimation, this work has adapted and investigated the use of a published battery model of the eye. When this was used on offline baseline drift-mitigated EOG data, a horizontal and vertical gaze angle (GA) estimation error of 2.23±0.48° and 2.39±0.54°, respectively, was obtained, which compared well with the 2.13±0.41° and 2.30±0.53° errors obtained using the state-of-the-art two-bipolar-channel input linear regression models. However, in contrast to such black-box regression models, the battery model is an explicit, anatomically-driven model which makes it easier to model more complex ocular behaviour. This work has also proposed the use of the battery model in a novel offline baseline drift mitigation technique which exploits knowledge of the targets which the subject attended to during EOG signal acquisition. Unlike the state-of-the-art-methods, this does not require the data to be zero-centred nor does it disrupt the EOG signal morphology. This technique was shown to yield a generally superior performance when compared to the existing techniques. The battery model is further augmented to represent the blink-related eyelid-induced shunting and this is used to dynamically model fixations, saccades and blinks within a multiple-model GA estimation framework while simultaneously handling the baseline drift in real-time. When applied to short data segments, a horizontal and vertical GA estimation error of 1.64±0.82° and 1.97±0.34°, respectively, was obtained, which compared well with the 1.51±0.55° and 1.95±0.29° errors obtained using the state-of-the-art method, whereas the proposed method resulted in a statistically significantly superior GA estimation performance on longer data segments. This framework achieved a global eye movement detection and labelling F-score exceeding 90%. This work also lifts the stationary head constraint that has been generally enforced so far in the literature. Specifically, this work generalises the two-eye verging gaze geometry to cater for an arbitrary head pose and position, and also models vestibulo-ocular reflexes (VORs) in the proposed multiple-model framework. Using the proposed method, a horizontal and vertical GA estimation error of 1.85±0.51° and 2.19±0.62°, respectively, and an eye movement detection and labelling F-score of approximately 90% was obtained. Description: Ph.D.(Melit.) 2022-01-01T00:00:00Z /library/oar/handle/123456789/106690 Title: An affordance-based design task clarification framework for speech and language therapeutic toys Abstract: The task clarification stage is characterised by a high degree of uncertainty due to the lack of information available to the designer at the beginning of a new design project. For this reason, designers find this stage the most challenging, especially if the designer does not know the context in which the proposed artefact and its end users will operate. Given that the success of a new product highly depends on how well the product requirements have been elicited, communicated and understood by the designer, early design support in this regard would alleviate the activities within the task clarification and subsequent design stages. The motivation of this research concerns early childhood speech and language therapy (SLT), which is facilitated through toys and play. For SLT to be effective and efficient, therapy must continue beyond the clinical setting. For this reason, apart from speechlanguage pathologists (SLPs), caregivers have a relevant role in treating language disorders in children. Thus, the end users of intentionally designed therapeutic toys for SLT, referred to as speech and language therapeutic toys (SALTTs), are the clinicians (SLPs), caregivers and children. Through research carried out in this dissertation, it was established that the affordances of toys highly influence children’s attention span and engagement with toys. Moreover, affordances permit designers to understand how a product will be used by its users. A literature review determined that designers lack a suitable means by which designers can elicit affordance-based end-users requirements for SALTT. By looking at the affordances that SALTT artefacts need to offer during their use phase, the descriptive Speech and Language Therapy Potential Model (SALT-PM) was developed. A prescriptive framework architecture, Design of Speech and Language Therapeutic Toys (D-SALTT), was also proposed to support novice and experienced designers to elicit and understand end-users affordance-based requirements. These were implemented in a prototype computational tool called ACQUAINT-SALTT. The evaluation of the D-SALTT framework architecture and ACQUAINT-SALTT showed that practising designers positively welcomed the provided user-centred design support for the task clarification stage, particularly the efficiency by which affordance-based requirements can be elicited, enabling them to understand the context of the end users without restricting their creativity. Description: Ph.D.(Melit.) 2022-01-01T00:00:00Z